Note: I really wanted to write a Gymnasticsshipping mermaid AU somehow, so I thought hard about it, and this is what I got!

Disclaimer: I don't own Taiki, Sachi, or the other Yu-Gi-Oh! Zexal characters. I also don't own Yu-Gi-Oh! Zexal.

Sea Legs

Chapter 1: The Merman in Heartland

The sun was bright as it shined down on the city; its beams of light reflected on the metal buildings, the surface of the sea, and the rivers running throughout the city. You could say that it was a breathtaking sight with the lights shimmering on the surfaces like diamonds.

This was especially agreed upon by three elementary kids, who were enjoying the nice weather as they frolicked next to one of the rivers.

"Watch this!" Sachi grinned at her friends before performing a cartwheel on the grass; her hair flying around as she flipped and landed her feet back on the ground. The two girls cheered and clapped after she had finished.

"That was amazing, Sachi!"

"Yeah! You're a great gymnast, Sachi!"

She giggled. "Thanks, Kotori. Thanks, Sei. Though, I still have a lot to learn."

"Hey! Believe us, you are great!" Sei exclaimed. She then pointed at herself and Kotori. "I mean, we don't even know how to cartwheel like you!"

"You two can master a cartwheel with enough practice." Sachi's smile grew bigger as an idea came to mind. "How about I teach you?"

Kotori and Sei smiled back, and soon, the air was filled with the sound of laughter as they attempted many cartwheels while Sachi instructed them. The girls eventually slowed down, watching as Sachi demonstrated how to cartwheel.

After explaining how the body should be positioned, Sachi posed and went through the motions. Move forward on starting leg, move arms toward the ground, push hands against the ground while raising the back leg in a rotation annnd…stick the landing. Sachi, satisfied with her cartwheel, took a step forward.

Usually, the fields next to the rivers were spotless thanks to landscapers and cleaners because they would remove any debris like sticks or leaves, allowing people to sit and relax. Unfortunately, they had missed removing a rock. So, when Sachi walked forward, she didn't notice the rock was right in front of her.

Not only that, but she also didn't realize how close to the water's edge she was.

Her foot hit the rock, causing her to trip. Unbalanced, she was unable to stop herself from falling. She let out a yelp…and then fell into the river.

The cold water surrounded her, swallowing her up as she sank down. Sachi flailed about under the water, panicking as she tried to figure out which way was up with shut eyes. She won't be able to hold her breath for long, and if she can't get back to the surface for air then…

Suddenly, Sachi feels something grab her hand. She holds on to what caught her, feeling the familiar shape of another person's hand. Wait…who was that? She calms down, feeling relief that someone was helping her, and opens her eyes. Her vision is blurry in the water at first, but she squints, blinks, tries to see who it was. She can make out a figure- a boy her age. She can sort of see his face, see some faint details like navy blue hair and a pair of…orange eyes? But the more she tried to see who it was, the more details she saw that didn't make sense. Like right where his ears would be, there was something pointier and more colorful. And his legs…was that a fish's tail?

Her thoughts are interrupted when the boy quickly pushes her up to the surface. Her head pops up out of the water and she gasps, breathing heavily. She makes her way to the edge, noticing how the river had carried her a bit down the sidewalk. She could tell because Kotori and Sei were currently running to the spot where she emerged, screaming out her name.

The two helped pull her out of the river, and Kotori examined Sachi with a worried look. "Are you okay?"

"Yeah, I'm okay," Sachi looked around. That boy should have resurfaced by now. "Someone helped me swim to the surface. It was a boy…did you see him?"

Sei raised an eyebrow. "Wait, there was a boy? No one else was here except for us."

"Huh…?" Sachi's eyes widened. She couldn't have imagined that, right? She stood there in shock, her arms hugging herself as she shivered.

"Let's head to my house. You can borrow some of my clothes and warm up there." Kotori suggested, immediately noticing Sachi's discomfort. She and Sei lead her away from the river, Sachi giving one last glance at it before following them. Eventually, the girls arrived at Kotori's house. They were greeted by Kotori's mother, who took one look at Sachi and frantically ushered her inside for a warm bath and some dry clothes.

After Sachi finished, the girls hung out in Kotori's bedroom, relaxing and chatting. Well…not really chatting since Sachi was quieter than usual.

"Are you sure you're okay?" Kotori asked her. "You've been way too silent. Is there something on your mind?"

"Oh, it's just…" Sachi sighed, gazing into her cup of hot chocolate. Kotori's mother had given it to her to help warm up and increase body temperature, which she agreed was helping; her hands wrapped around the cup to absorb the warmth coming from it. "You guys really didn't see a boy?"

Sei leaned back into the chair she was sitting in, frowning. "Sorry, Sachi…but there was no one else there."

Sachi fell silent again, thinking back to the moment she had seen that boy. She remembered there had been certain details about him that didn't make sense. She thought hard. First, his ears were pointy and colorful. The shape was like…ah yes! His ears were shaped like the fins of a fish. Last, were his legs- or lack of legs. Hadn't the shape been similar to that of a fish's tail?

So, a person who looked half human and half fish? She heard that description before- it matched something she only heard about in fairytales. So that means…

"I know what I saw now!" exclaimed Sachi, startling the two girls. Sei and Kotori stared at her with curiosity, and Sachi stared back with a serious look in her eyes.

"I saw a merman!"

It was their turn to be quiet as they processed what she just said. Sei was the one to break the silence.

"A merman? You mean like the mermaids told in fairytales?" She was surprised when Sachi nodded her head. "But those are just stories, right? Do merpeople actually exist?"

"Maybe they do…" Kotori murmured; her chin perched on her hand as she thought, but then sends a sheepish smile to the girls. "Though, we don't have proof."

Sachi takes a sip from her cup and then pouts. "But I know I saw one…"

After that day, Sachi found herself searching for any signs of the merman who helped her. While Sei and Kotori weren't quite sure about his existence, they still supported her, even helped her investigate at times.

Sachi wondered where the boy could have gone off to. She and the girls checked around as much as they could, to the best of their abilities. There were no signs of him at the river she fell into, nor at the other rivers that ran throughout the city. He probably swam back to the ocean, though part of her still hoped that he was still around somewhere. How else was she going to thank him?

As time passed, the investigation slowly became abandoned. With no results, the encounter faded into the past, yet the memory still lingered on in Sachi's mind.

"Good morning!"

Sachi smiled brightly as she greeted Kotori and Sei. Both girls smiled back, greeting her in a similar fashion. The three of them, now in middle school, were waiting for the monorail that would take them to the school building. They chatted about the schedule for the day, like how classes would turn out, until the monorail arrived at the station. Many other students wearing blue uniforms, green uniforms, red uniforms, and the pink uniforms that the girls were wearing walked onto the monorail. The three got on as well, gazing at the city below them as the ride smoothly made its way to their destination.

They got to their classroom on time, waving at their fellow classmates as they took their respective seats. Sachi was already thinking about practicing at the gymnastics club and was ready for another regular day when the teacher entered the room.

"Good morning, everyone." said Professor Ukyo. "Today, we have a new student joining our class."

A low murmur began to rise at the announcement of a transfer student. The professor smiled in response, turning his head towards the door. "Please come in!"

The door slid open, and a boy walked in, following the professor to the front of the room. Ukyo held up a D-Pad, instructing him to write his name, which was then shown on a huge holographic screen.

"My name is Kimura Taiki," the boy said. "It's nice to meet you all."

Professor Ukyo gestured a hand toward an empty seat. "Taiki, how about you sit over there?"

Taiki nods and proceeds to walk through the aisle to his assigned seat. Sachi examined him, and just as he was about to pass by her desk, he glanced over, and their eyes met.

At that moment, she felt transported back to the time when she was little, when she had fallen into the river. A pair of orange eyes stared back like the eyes of the mysterious merman. It only lasted for a second before he looked away, leaving her sitting there in shock.

Class then began, but Sachi couldn't concentrate. There was almost something familiar about him, and there were similarities like the navy-blue hair along with the orange eyes. But Taiki was human, not a merman. Sachi shook her head and tried to pay attention to the teacher.

Soon, the bell chimed, signaling the end of class.

"Hellooo, Earth to Sachi?" Sei placed her hand on her hip, studying the slow response from her friend. "You've been staring at the new guy for a while. What's up?"

"I feel like I've seen him before," Sachi explained.

"Really?" Kotori takes a quick look at Taiki and then returns her gaze back to her. "From where?"

"Okay, this might sound strange but…" Sachi blushed, embarrassed. "…remember when we were kids and I fell into the river? Taiki reminds me of the merman that rescued me."

Kotori and Sei blinked in disbelief. "Maybe you're just interested in him. I'm pretty sure Taiki is human." Sei teased, causing Sachi to blush even more.

"I know, but he feels almost familiar,"

"I think you're mixing them up. That's in the past now." Sei chuckled. "Are you saying that Taiki is a merman?"

Sachi realized she was right. Maybe there was a fleeting thought that they were the same, but it was silly. There was no reason, no proof to believe that.

It was like saying a merperson could do gymnastics. There is no way a mythical creature like that can do gymnastics.

Sachi softly smiled, a small giggle escaping from her lips. "No, I guess not."

"Why don't we go introduce ourselves?" Kotori motions toward Taiki, who was sitting at his desk. The girls agreed, making their way to him; Taiki looked up as they approached.

"Hey! You're the new student, Taiki, right? My name's Sei, and this here is Kotori and Sachi!" Sei pointed them out with a huge grin.

"Yeah, that's me. Nice to meet you three." he replied calmly, his expression neutral yet he seemed amused.

"We just wanted to say welcome to our school! Since you're new here, why don't you try out the clubs? It's a great way to meet new people and socialize." Kotori chimed in.

"Kotori, you sound like an advertisement." Sei giggled. She pretended to duck as Kotori turned to playfully slap at her in an annoyed manner with puffed cheeks, yet she too was laughing.

"Actually, I heard this school has a gymnastics club. Is that true?" Taiki asked.

Sachi perked up at the mention of the club. "Yeah, that's true! I'm actually part of the team."

He looked at her, a slight smile growing on his face. "Really? So, you're a gymnast too?" She nods, delighted to hear that he was a gymnast like herself.

"Cool. I love gymnastics, but my old school didn't have a club. My parents and I moved to this area recently due to their work, so I was planning on joining it." Taiki explained.

"That's perfect! Sachi can show you where the club is." Sei exclaimed.

"Yeah! I have practice right after school today. If you want, you can follow me there." Sachi offered.

Taiki smirked. "Thanks, I'll do that. I'm not entirely sure where it is."

After school, Sachi showed him the club building, where he met the coaches. He was asked to demonstrate his skills, which he did.

Oh wow. He was good; his skills on the horizontal bar were great! It wasn't long before he got comfortable with the team, even becoming the ace of the club.

Sachi got to know him little by little. Taiki was a serious person, always working hard on being a gymnast, yet there was also a softer side that showed up whenever he'd laugh or smile.

There was another fact about him that Sachi learned. As a first-year student, you had to take a swimming class. Even though Taiki was a first-year, he did not have to, and there was a reason why.

"You don't have to take swimming class? How come?" Sei had asked him, curious.

This caused Taiki to frown. "I can't swim. Never was able to learn when I was a kid because I had a bad experience with water."

Sei quickly apologized afterwards.

Perhaps that was why he had been acting strangely around water. One time, during one of their breaks at practice, she noticed that he had finished his bottle of water, so she offered him an extra bottle she had with her. He was quiet but, in the end, he accepted it. It was almost as if he was being cautious; he even drank the water carefully, not even spilling a drop.

Was that why he would run off in his coat without another word whenever it rained?

Could it be he almost drowned, and the traumatic event caused him to avoid water?

Sachi wanted to find a way to help him. She wanted to protect his happiness…and she wanted to protect him.

"Great job at practice today, Taiki-kun!"

"Thanks. You were pretty great yourself."

Sachi just giggled a reply. She was glad that Taiki had agreed to walk with her after practice, and the two of them were now sitting on the grass after they had stopped by one of the rivers.

Now that she thought about it, wasn't this river the one where she…

Sachi ignored the incoming thought, leaning back against her palms, staring at the clouds in the sky. "You work so hard; you must have a dream."

Taiki turned away from the sky to glance at her. "A dream?"

"Yeah! Like a goal you want to accomplish," Sachi closed her eyes, smiling softly. "I think my goal is to get better as a gymnast."

Taiki sat there in silence, deep in thought. He wanted to tell her, but he couldn't figure out the right words.

He looks at her, his eyes softening. "My dream-"

Without any warning, a raindrop fell from the clouds. At first, it was only a couple of slow ones but then tons of raindrops began to fall at a rapid rate.

"Oh no!" Sachi stood up, her hands raised above her head in an attempt to shield herself from the rain. She turned to where she left her bag, trying to hurry and grab the umbrella inside.

Taiki had already done the same, rummaging through his bag, but it was too late. The rain had already soaked him, his dark blue tracksuit wet and hair dripping.

That wasn't his only problem.

Taiki hissed under his breath. He let his guard down. He didn't expect a sudden rainstorm, but he should have been more careful.

And now, he could feel his form changing through his skin.

He couldn't let Sachi see him. There was no time to run, only one option remained. He glanced over to where she had her back turned, sending her a silent apology, and then quickly slipped into the river.

Sachi thought she heard a splash, dismissing it as soon as she got her umbrella. Yet, when she turned back around, ready to give it to Taiki, she found herself all alone. She blinked, confused. Where did he go? Did he run off by himself again?

There was that splash she heard. Could that have been…

Dread began to creep up her skin as she stared at the river in horror. Did Taiki accidentally fall in when the rain started pouring?

He fell in…and he can't swim.

"Taiki!" Without any hesitation, Sachi jumped into the river. She was a better swimmer than before, so she had no problem as she swam down, her eyes squinting as she searched for Taiki. Though her vision was blurry, she managed to spot his body sinking down; she reached out and grabbed his hand.

Taiki jerked his head up in response to the sudden contact, his eyes widening at the sight of Sachi. He allowed her to guide him back up to the surface.

Two heads popped out of the water with a splash. Sachi gasped, her chest heaving as she breathed in much needed oxygen, Taiki holding her shoulders, cradling her close to him as they floated.

Taiki's eyebrows furrowed, expressing his anger. "Idiot… What were you thinking, jumping into the river?"

"I heard you fall in," Sachi said, wiping water out of her eyes. "There's no way I would leave you like that- not when you can't swim. Of course I'm going to jump in and rescue you."

He was stunned. She was smiling sheepishly, despite having just jumped into a river to help him. Taiki's grasp on her shoulders tightened, like he was afraid to let her go.

Sachi finished wiping her eyes; her vision returned to normal. She tilted her head up to look at him. "Are you okay-"

Her eyes widened, the expression on her face turned into one of surprise at the sight before her. Taiki's appearance had changed. A pair of fins replaced where his ears had been, sticking out of his wet hair. He no longer wore his tracksuit, and she could see patches of thin, navy-blue scales on his body, his tail covered entirely of them.

"Taiki…?" Sachi whispered. "Is that you?"

His head was tilted to the side, avoiding her gaze. He sighed when she called him, turning to face her, his eyes meeting with her own. A nervous, small smile grew at the corners of his lips. "Yes Sachi… it's me."

When he said that, the memory of the merman resurfaced in Sachi's mind, the face of the young boy becoming clearer. It was Taiki's face that appeared; it had been him who saved her. The similarities…the orange eyes and navy-blue hair…

The merman and Taiki were one and the same.

Sachi smiled, happy tears mixing with the rain on her cheeks. "It is you."

Note: This was originally just going to be a one-shot story, but then I thought about splitting up the story into multiple chapters, so more to come soon.